• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

97 HELLLP PLEASE PO123 TPS

whitexj98 said:
Well trace the wire back, it must be shorted somewhere but like I said eariler, have you folowed the checks they list out in the FSM for P0123?
Click to expand...
yes I have. and with multiple harnesses having been switched out with the same result you tellin me they are all like that? I would not think so...
 
whitexj98 said:
So you traced the disconected wire and it not shorted to anything but it still shows voltage?

Acording to the FSM that orange wire also splits up to the cam shaft position sensor, try checking voltage with that disconnected too.
Click to expand...
I did; I disconnected everything fed by that orange wire; if i (individually) connect the CPS the MAP OR the TPS my TPS voltage goes from 4.67 to 4.94; the front O2, the dist pickup or temp sensor do not have that effect. if everything is connected except the TPS it makes the same change when I plug it in; being that under normal conditions (everything working) key on eng off throttle not touched, TPS voltage should be about 1/4 volt, I am getting that amount of difference between TPS connected/disconnected, so that leads me to believe the TPS isn't the issue. How can I show a reading of 4.67 with the TPS unplugged?
again this reading was verified by the Fluke meter. to the 2nd decimal, identical reading.
it makes sense for the TPS reading to not change much as throttle applied being it shows 87% when "untouched" I havve a 100% swing of the throttle and only 13% sensor range with which to do it. and again; 2 other different harnesses have been installed on this Jeep with identical results; I wouldn't think I have 3 bad harnesses?
 
volaredon said:
so the black/orange and the orange are supposed to both have juice on them?
I had juice on my grond one as well/ my mind is on knots with this thing.

one thing I am gonna do, is to re install my orig underhood wire harness since the one I found in the JY was a "less loaded" one, and TPS wise all my results are identical to with the orig harness.

I will have both a 97 and a 98 XJ underhood harness for sale and soon.
Click to expand...


if your getting voltage at ground. you have an open on the ground side after the tested area. look up the wiring diagram and start testing at connectors to detect area error occured
 
rafajrbarajas said:
if your getting voltage at ground. you have an open on the ground side after the tested area. look up the wiring diagram and start testing at connectors to detect area error occured
Click to expand...
Grrr; thats what I have been doing since july.....and 2 replacement harnesses later still at square 1
 
well putting 2 other wire harnesses on proved my orig is OK since I still have the same problem so I'm gonna re install the originl for starters.... (I know that wont solve anything but since I have the same issue with the replacements that says the orig is OK and since mine is a fully loaded "Country" there are a couple "accessory" terminals missing in the underhood fusebox, I may as well have my foglights back...)

BTW; I see alot of 4 door vehicles these days marked as "Sport" models; (not just Jeeps) Since when is having 4 doors "Sporty"????
I have a TJ which is also a "sport" no extra doors there; I thought at one time I might want a Dodge Charger; this being back in 99 when the prototype was making teh Auto Show rounds as a 2 door; they totally ruined that car; heck its hard to find a pickup that isn't a freakin crew cab these days, makes me sick.
yes unfortunately mt XJ is a 4 door; (but the wife drives it) she wants bigger tires and a lift, I tried to make a deal with her that we trade the 4 door XJ for a 2 door, I'll buy a lift for it.... she said "no" so our XJ remains stock.

now back to trying to figure out how to get the thing running again.
 
rafajrbarajas said:
no need to get mad. stress will just make it harder to solve.have u checked the data bus on the pcm.
hook a scan tool to it and check your data bus signal.
Click to expand...
I have been mad at this thing since about the beginning of August...
the data bus must be OK as I get readings for all the available parameters... and other than the TPS reading all of the rest seem "normal";
and I aint mad at you, just aggravated and frustrated with this Jeep and my wife not seeming to understand why i can't figure it out....
all she knows is that til i do she has to drive a stick (my TJ) and she don't like it; she is threatening at least once a week to call off work, not to have to drive the TJ to get there.... (I am gettin tired of hearing that)
specifically what should I be looking for in the data bus stream?
 
I didn't realize there were actually 5 seperate books that make up the 97 cherokee FSM; I have only the "main" one; after re reading some sections in there and being referred to the Powertrain Diagnostics manual (seperate book) and being asked if I had "that" book by a responder to my problem on another forum I looked on Ebay and found it so I have that and the "body" one coming now. I dont need the ABS one (y XJ dont have) nor do I currently need the AW4 one...yet.
I think the powertrain one is the one with all the flow charts and verification tests listed.
While I wait for my copy to arrive from pennsy
via Ebay, I think i'l call my dealer buddy and see if I can borrow the dealer's copy for the weekend. had I known there was more "books" that made up this manual earlier I might hav ebeen able to figure this thing out sooner than 4 months after it started acting up...

Thanks for the suggestens and please KEEP EM coming!!!

I will post once I figure this mess out for future reference;
 
you have a lot of "must be"s and "dont need to check"s ... it can take a long time that way
 
well Volaredon your not the only one out there with this issue. I went through the carwash at my work at the engine died half way through. (always scared me since I removed my splash guards and theres some pretty aggressive jets that spray the undercarriage) Got a P0123 code. Cleared the code with my scanguageII, waited 10 mins after trying to fire her up. Finally got her going and drove home with no issues. The next morning I go to drive it and the rpms went crazy on me, sure enough P0123 popped up. Today I bought a new TPS and installed it only to find that now every time I start the jeep it redlines! What does your throttle body valve look like at idle with the TPS on? My new TPS would not go on until it opened the valve a little bit. I could've swore it is supposed to be flat at idle but I cant remember for sure.

p.s. Im glad to know someone with a stock xj has this problem as well. I was worried that with all the electrical "upgrades" one of em may have shorted.
 
Well I fixed my issue just now. I had to remove the throttle body, then proceeded to install the TPS, turn tps 1/8 of a turn counter-clockwise then seat it to the surface of the throttle body and turn clockwise to align holes. I then disconnected the battery and touched pos and neg. together for thirty seconds. bolted everything back up and fired her up! good as new.
 
Off topic, but something to keep in mind... I had a '97 SE, and HATED it. There were so many crossover parts i was ridiculous. A lot of the stuff carried over from '96 which made shopping for parts IMPOSSIBLE unless you have the part physically in front of you.
 
Ya it is. I've just never had to replace one on my 97 or 99 before so I guess they differentiate from the 96-. The TPS I replaced on both my 89's and both my 90's didn't require removing the throttle body.
 
Re: 97 HELLLP PLEASE PO123 TPS FIXED!!!!! (long)

larsen said:
you have a lot of "must be"s and "dont need to check"s ... it can take a long time that way
Click to expand...

Huh? what do you mean by that??

Anyway I GOT THIS THING FIXED TODAY finally.. and the solution does not make full sense to me;
Being a full time college student at 44, I have needed my mind and my time for other things; so the jeep has sat collecting dust and is starting to get stuff piled in/on/around it in the garage. good thing I own 2 more vehicles than I have drivers in the house. otherwise I would have been screwed.
I got the other parts to the 97 FSM in the mail, a while back; (I now have 3 of the 5 books that make up the whole series) and I went thru the "TPS too high" flow chart as soon as I opened them up; and following all the appropriate "Yes' and No's" in the flow chart, it said "REPLACE TPS";
the manual did not get as into depth as I did, meaning that alot of what I replaced, disconnected, and multimeter checks that I did, were not even talked about through out that particular flow chart;
I did not want to believe it, because alot of the voltage checks I did were confusing and contradictory.

Another jeep specific forum that OI posted on, said "REPLACE CLOCKSPRING and be done with it"; being on Disability these last 4 years (money being way short, compared to my past working days) I could not see spending the $156, knowing that it may solve it and may well not do anything for me; that forum said that if I unplugged it and it was the problem, my TPS readings would come back and the code would go away. (it did NOT) but they still insisted that had to be "it";

As I posted here earlier>>> told the wife the same thing>>>, I could replace every dam sensor under the hood, and not solve anything but be "broke-r" from it having wasted the $$ on parts that did nothing to solve; when I was working, I may well have done that very thing. but I also know that 5 sensors get their ground from teh same ground as the TPS and 4 use the same 5V REF; thinking "series circuit" (Christmas tree lights are wired this way) I finally decided to buy several sensors and my original thought was to replace them en masse on account of age; if that did not do the trick the clockspring would be next.
Well I didn't do that either; I bought a new pre cat O2, a new crank sensor and a TPS from Rockauto; (I bought their most expensive choices for all hoping, for US made parts all "STANDARD" brand and none American,, crap)
well. I put the new TPS on and figured why not try it; I started the engine and NO CHECK ENGINE LIGHT! scanner showed normal TPS readings;

this makes no sense at all; having traced the wiring diagrams as much as i did and seemingly having voltage in way too many places that it did not belong; going back to that flow chart part of the FSM and not seeing any references for that code, referring to about 2/3 of the things I tested for. Even though it was a natural progression based on the flow of teh wiring diagrams

add in that with the old TPS on it I had exact same reading whether connected or not; and that known good used one that I tried on there waaaay back. which led me to believe no change=eliminate as a possibility, old sensor must be OK. that thinking actually turned out true for the clockspring though.
but all this crap and a 6 month garage ornament for a dam TPS...... I'm both happy and pi$$d;
I will put my new O2 in anyway because the current one is 15 years and 125K miles old; besides I would have to pay shipping to send it back; the crank sensor will go in the glovebox as a spare since I know that is another common thing to die on these engines.

My next step I was looking at doing, was tearing out the dash to pull that harness completely out, to look for other collateral damage caused by having had the aftermarker remote start setup in there.....another reason it sat as I am not as comfortable laying under the dash working "upside down" as I was in my younger days. I'm so glad I didn't have to "go there".
 
Re: 97 HELLLP PLEASE PO123 TPS FIXED!!!!! (long)

volaredon said:
Huh? what do you mean by that??

Anyway I GOT THIS THING FIXED TODAY finally.. and the solution does not make full sense to me;
Being a full time college student at 44, I have needed my mind and my time for other things; so the jeep has sat collecting dust and is starting to get stuff piled in/on/around it in the garage. good thing I own 2 more vehicles than I have drivers in the house. otherwise I would have been screwed.
I got the other parts to the 97 FSM in the mail, a while back; (I now have 3 of the 5 books that make up the whole series) and I went thru the "TPS too high" flow chart as soon as I opened them up; and following all the appropriate "Yes' and No's" in the flow chart, it said "REPLACE TPS";
the manual did not get as into depth as I did, meaning that alot of what I replaced, disconnected, and multimeter checks that I did, were not even talked about through out that particular flow chart;
I did not want to believe it, because alot of the voltage checks I did were confusing and contradictory.

Another jeep specific forum that OI posted on, said "REPLACE CLOCKSPRING and be done with it"; being on Disability these last 4 years (money being way short, compared to my past working days) I could not see spending the $156, knowing that it may solve it and may well not do anything for me; that forum said that if I unplugged it and it was the problem, my TPS readings would come back and the code would go away. (it did NOT) but they still insisted that had to be "it";

As I posted here earlier>>> told the wife the same thing>>>, I could replace every dam sensor under the hood, and not solve anything but be "broke-r" from it having wasted the $$ on parts that did nothing to solve; when I was working, I may well have done that very thing. but I also know that 5 sensors get their ground from teh same ground as the TPS and 4 use the same 5V REF; thinking "series circuit" (Christmas tree lights are wired this way) I finally decided to buy several sensors and my original thought was to replace them en masse on account of age; if that did not do the trick the clockspring would be next.
Well I didn't do that either; I bought a new pre cat O2, a new crank sensor and a TPS from Rockauto; (I bought their most expensive choices for all hoping, for US made parts all "STANDARD" brand and none American,, crap)
well. I put the new TPS on and figured why not try it; I started the engine and NO CHECK ENGINE LIGHT! scanner showed normal TPS readings;

this makes no sense at all; having traced the wiring diagrams as much as i did and seemingly having voltage in way too many places that it did not belong; going back to that flow chart part of the FSM and not seeing any references for that code, referring to about 2/3 of the things I tested for. Even though it was a natural progression based on the flow of teh wiring diagrams

add in that with the old TPS on it I had exact same reading whether connected or not; and that known good used one that I tried on there waaaay back. which led me to believe no change=eliminate as a possibility, old sensor must be OK. that thinking actually turned out true for the clockspring though.
but all this crap and a 6 month garage ornament for a dam TPS...... I'm both happy and pi$$d;
I will put my new O2 in anyway because the current one is 15 years and 125K miles old; besides I would have to pay shipping to send it back; the crank sensor will go in the glovebox as a spare since I know that is another common thing to die on these engines.

My next step I was looking at doing, was tearing out the dash to pull that harness completely out, to look for other collateral damage caused by having had the aftermarker remote start setup in there.....another reason it sat as I am not as comfortable laying under the dash working "upside down" as I was in my younger days. I'm so glad I didn't have to "go there".
Click to expand...

So in the end the new TPS fixed the problem?
 
I fixed that entire post for you :)

Originally Posted by volaredon
Huh? what do you mean by that??

Anyway I GOT THIS THING FIXED TODAY finally.. and the solution does not make full sense to me;
Being a full time college student at 44, I have needed my mind and my time for other things; so the jeep has sat collecting dust and is starting to get stuff piled in/on/around it in the garage. good thing I own 2 more vehicles than I have drivers in the house. otherwise I would have been screwed.
I got the other parts to the 97 FSM in the mail, a while back; (I now have 3 of the 5 books that make up the whole series) and I went thru the "TPS too high" flow chart as soon as I opened them up; and following all the appropriate "Yes' and No's" in the flow chart, it said "REPLACE TPS";
the manual did not get as into depth as I did, meaning that alot of what I replaced, disconnected, and multimeter checks that I did, were not even talked about through out that particular flow chart;
I did not want to believe it, because alot of the voltage checks I did were confusing and contradictory.

Another jeep specific forum that OI posted on, said "REPLACE CLOCKSPRING and be done with it"; being on Disability these last 4 years (money being way short, compared to my past working days) I could not see spending the $156, knowing that it may solve it and may well not do anything for me; that forum said that if I unplugged it and it was the problem, my TPS readings would come back and the code would go away. (it did NOT) but they still insisted that had to be "it";

As I posted here earlier>>> told the wife the same thing>>>, I could replace every dam sensor under the hood, and not solve anything but be "broke-r" from it having wasted the $$ on parts that did nothing to solve; when I was working, I may well have done that very thing. but I also know that 5 sensors get their ground from teh same ground as the TPS and 4 use the same 5V REF; thinking "series circuit" (Christmas tree lights are wired this way) I finally decided to buy several sensors and my original thought was to replace them en masse on account of age; if that did not do the trick the clockspring would be next.
Well I didn't do that either; I bought a new pre cat O2, a new crank sensor and a TPS from Rockauto; (I bought their most expensive choices for all hoping, for US made parts all "STANDARD" brand and none American,, crap)
well. I put the new TPS on and figured why not try it; I started the engine and NO CHECK ENGINE LIGHT! scanner showed normal TPS readings;

this makes no sense at all; having traced the wiring diagrams as much as i did and seemingly having voltage in way too many places that it did not belong; going back to that flow chart part of the FSM and not seeing any references for that code, referring to about 2/3 of the things I tested for. Even though it was a natural progression based on the flow of teh wiring diagrams

add in that with the old TPS on it I had exact same reading whether connected or not; and that known good used one that I tried on there waaaay back. which led me to believe no change=eliminate as a possibility, old sensor must be OK. that thinking actually turned out true for the clockspring though.
but all this crap and a 6 month garage ornament for a dam TPS...... I'm both happy and pi$$d;
I will put my new O2 in anyway because the current one is 15 years and 125K miles old; besides I would have to pay shipping to send it back; the crank sensor will go in the glovebox as a spare since I know that is another common thing to die on these engines.

My next step I was looking at doing, was tearing out the dash to pull that harness completely out, to look for other collateral damage caused by having had the aftermarker remote start setup in there.....another reason it sat as I am not as comfortable laying under the dash working "upside down" as I was in my younger days. I'm so glad I didn't have to "go there".
Click to expand...
 
lol ... from the first post:

volaredon said:
... I am getting 4.69V at TPS with TPS UNHOOKED and 4.92V by plugging it in. key on engine off, scanner says 87% gas pedal application whether the pedal is touched or not.
so being that I am getting those readings unhooked I can eliminate TPS as the cause. ...
Click to expand...
 
Last edited:
You must log in or register to reply here.

Similar threads

C
Transmission Not Shifting Past First Gear
Replies
4
Views
132
cruiser54
C
O
2000 XJ Failed Colorado Emissions high CO
2
Replies
27
Views
2K
Ken M
K
P
2K IDLE - Odd Shifting - TPS? (I know.. I know)
Replies
3
Views
2K
Unclewolverine
U
J
2001 4.0L issues
Replies
15
Views
292
Saudade
Saudade
C
'98 XJ p0123 help, TPS high voltage
Replies
18
Views
3K
Tim_MN
Tim_MN
Back
Top